
#include<iostream>
using namespace std;
int main()
{
	int i=0;
	int sum=0;
	double finally;
	int A[11];
	//cin>>A[0]>>A[1]>>A[2]>>A[3]>>A[4]>>A[5]>>A[6]>>A[7]>>A[8]>>A[9];
	for(i=0;i<10;i++)
	{
		cin>>A[i];
		if (A[i]>=0&&A[i]<=100){
			sum = sum+A[i];
		}
		else{
			cout<<"the score is invalid.";
			break;
		}
		finally = 1.0*sum/10;
		cout<<finally;
	} 
	
	return 0;
}
